The typical vehicle suspension includes a damper in the form of a strut or a shock that is mounted between the sprung (body), and unsprung (wheel assembly) masses of the vehicle to dampen spring oscillations. The lower end of the damper is connected to the wheel assembly in a suitable manner and the upper end is connected to the vehicle body's structure, usually at a tower, by an upper damper mount assembly. With conventional upper mounts, the coil spring supports the weight of the vehicle and creates a force that is proportional to the relative velocity between the vehicle's wheel and its body, transferring loads to the mount. In addition, a jounce bumper acts as a stop for compression directed movement of the damper transferring loads to the mount. Since the damper is connected to the body by the upper mount, the upper mount must support the total weight of the vehicle and provide acceptable isolation. Achieving these properties requires proper tuning of the mount. Tuning is complicated by the fact that relatively high spring and jounce bumper loads have to be accommodated through the mount.
Conventional upper mounts include at least one resilient element (rubber cushion), to isolate and reduce the transmission of input forces to the body. An upper mount is generally required to be firm enough to support the weight of the body while simultaneously resilient enough for isolation purposes. For certain inputs, deflection of the upper mount is desirable while for other inputs it is preferable for the upper mount to resist deflection. Single path upper mounts are known, wherein the actuator or damper rod and a coil spring seat are fastened together and the load path is through a single rubber cushion. The single rubber cushion accommodates the forces generated by both the actuator or damper and the cooperating coil spring. The rubber cushion is preloaded by the vehicle's weight. Dual path mounts are also known, wherein the actuator or damper rod and the coil spring seat are not fastened together and wherein the load path is through separate rubber cushion assemblies. A first rubber cushion assembly engages the coil spring and supports the vehicle's weight and the second rubber cushion assembly engages the actuator or damper rod and is not preloaded by vehicle weight.
The conventional upper mount assembly is attached to the tower by a plurality of fasteners that are distributed around the mount near its outer perimeter. It is also known to secure the mount to the tower by placing components of the mount on opposite sides of the tower and capturing them by a nut threaded to the piston rod tenon of the damper. Both of these techniques require a substantial number of components and can tend to be rather complicated. Accordingly, a need exists for a simplified upper mount assembly that is easily attached to the vehicle's tower and includes relatively few individual components.